Quantification of forces involved in stabbings

Stabbing is the most common way of committing murder in the UK. Sharp implements are used in stabbing attacks with the intent to cause injury and death. The number of deaths that result from stabs is high, partly because major organs and major blood vessels are relatively close to the skin and easily penetrated. Knight in the late 1970s used a spring loaded device to make stab tests into cadavers. He concluded that skin was easily penetrated by sharp knives and that skin offered the most resistance to penetration, with underlying fat and muscle requiring less force to penetrate. Knight concluded that the sharpness of the tip was the most important factor in determining whether a knife penetrated. Various other investigators have since investigated the effect of skin and various skin simulants, concluding that most items of clothing are easily penetrated by a knife, and considered how the geometry of the knife affects it sharpness. This thesis has looked at the effect of clothing on forces required for stabbing and the use of glass bottles as impulsive weapons. It has been found that clothing does influence the force required for stabbing. For the glass bottles it was found that there was no simple method for predicting how sharp a particular bottle would be once it was fractured. A novel dynamometer has been developed to accurately mimic a stabbing event and record the forces generated. The data shows that there are considerable differences in the forces generated by males and females; discernable differences between the dominant and non-dominant hand and that stabbing, even with blunt weapons can cause considerable penetration in most cases. The data also shows that the traditional ranking of mild, moderate and severe used by forensic pathologists lacks meaning in interpreting stabbing events.